[c-nsp] T3 or Ethernet delivery?

[Seth Mattinen]

Jon Lewis wrote:
> On Wed, 8 Apr 2009, Jeffrey Ollie wrote:
> 
>>> How do you detect a "down" condition on Ethernet? My experience is that
>>> the interface could be up/up because Ethernet doesn't know about
>>> anything further down the line and ends up throwing packets into a
>>> magical black hole. Or worse, secret packet loss.
>>
>> There's nothing unique to Ethernet about that...
> 
> No, but with ethernet, it's more likely that there's going to be a layer
> 2 "local device" (i.e. a switch) which you connect to, but the layer 3
> next hop is somewhere off on the providers network in another building. 
> When the network breaks somewhere between the provider's L3 next hop and
> your location, you'll still be up/up, but have no connectivity.  With
> BGP, you might tune the timers shorter than default so that such a break
> gets noticed sooner.  With a T3, BGP would find out about the break as
> soon as the interface went down.

In my case the next L3 hop is going to be in another state. For example
with Sprint, I'm in Reno, NV and their router is in Stockton, CA.

As far as the actual equipment, it will be an HWIC-1FE (HWIC-1GE-SFP if
fiber) or NM-1T3/E3 in a 3800.

~Seth